Combined light and heavy weight paper making machine



Jan. 17, 1933. M OBERDORFER ET AL 1,894,472

COMBINED LIGHT AND HEAVY WEIGHT PAPER MAKING MACHINE Filed March 12, 1932 In of 75/1! Patented Jan. 17, 1933 UNITED STATES 'PATEN'IEUOFFIC MAX OBEBDORFER AND J'O SEF E. RYBERG, OF ST; HELENS, OREGON COMBINED LIGHT AND HEAVY .WEIGHT PAPER LIA KING MACHINE Application filed March 12, I932. Serial No. 598,361.

Our invent-ion relates to an improvement in paper making machines comprising wet presses and felts as at present arranged.

Heretofore it required two different machines for making light weight and heavy weight papers. In other words, a machine designed for making heavy weight paper sheet required a different arrangement of its elements than the machine intended for making light weight paper sheet, because the web of paper in the one instance required different handling than in the other.

The object of our invention is .to provide a single machine adapted for making on it either heavy or light weight paper sheets.

The elements and their arrangement in our machine, by which we attain the objects of our invention, are illustrated in the accompanying drawing constituting a part of this specification.

Such drawing shows diagrammatically the combination of elements composing our machine sufliciently to enable anyone versed in the art of paper making to understand the nature of our invention.

Describing first the combination of elements which are used to make a light weight sheet:

a and I) represent respectively the couch press rolls; 0 represents the Fourdrinier wire;

at the pick-up or top felt; e and f represent the first press rolls; and z and 9' represent the transfer press-rolls.

The drier section 1*. of our machine is the same whether our machine is to be used for making a light weight paper sheet or a heavy weight paper sheet.

In order to adapt our machine for making on it also a heavy weight paper sheet, we combine with the elements above described, a second pair of press rolls 9, h.

We will first describe the operation of our machine for making a light weight paper sheet.

The light weight aper web is picked up b the pick-up or top elt d, as soon as the we has passed thru the couch press rolls a and b. The aper sheet clings by adhesion to the undersi e of the pick-up or top felt d, as is well understood, and is thus carried to and thru the-first press rolls 6, f and from there the paper sheet is still carried by adhesion on the underside of the pick-up or top felt d to the transfer rolls 2', j. At the latter point the paper sheet leaves said top-felt d and cllngs to the bottom transfer press roll i, and from thence is carried to the drier section 70. Meanwhile the pick-up or top felt dis led around the top transfer press roll back to the couch press rolls a and b.

In order to prevent the breaking of a light welght sheet it is necessary to extend the top felt d from the first press rolls 6, direct to the transfer press rolls 1) j. The described course of the light weight aper sheet thru the machine is indicated by t e arrows m.

The course of a paper web forming a heavy weight sheet is indicated by the arrows 3 The heavier paper web initially clin s to the underside of the pick-up or topfelt and h is carried by adhesion to such felt to thru the first press rolls 6, f.

In passing thru these press rolls the pa er web has had squeezed out of it a consi erable quantity of its moisture; in short, it is now much drier and much less adhesive; and besides it is also firmer and heavier. In

and

consequence, when the paper sheet has passed thru the first press rolls e, f, it leaves the pick-up or top felt 'd, and is then led over the roll Z on the lower felt n and on this to the second set of press rolls 9, h; and after passing thru the latter the sheet is conducted direct to the drier section is.

Answering in advance a question which may arise in considering the utility of our above described invention, namely:

Could not the top felt d be run between the second set of press rolls g, h and thus 2 neeaara tent between the top felt and the paper sheet as to form air blisters which shortly break and cause the sheet to break. To avoid such result, the to felt must be run from the first pressro s e, f direct to the transfer press rolls 5, j, as mentioned.

A heavier sheet of paper, on the other hand must be run thru a second set of press rolls, as g, h, to give it the desired density. If the m heavier sheet were to be carried by the top felt to the transfer rolls i and 15, after 1t had passed thru the second press rolls g and h, it would not only tend to fall ofi the top felt, but besides, the particles of air whic are entrapped between the dense top-felt and the heavier sheet of paper would accumulate and form air blisters breaking thru the sheet in a few seconds and cause it to break.

We, claim:

m 1. In a paper mahn machine, the combination with couch ro s, press rolls, transfer rolls and a drier section, and a top felt passing thru said couch rolls and press rolls and then returning over said transfer rolls,

of second press rolls located between the first mentioned press rolls and the drier section, said transfer rolls being located to arrange the path of travel of said top felt above sald second press rolls. i

2. In a paper making machine, the combination with couch rolls, press rolls, transfer rolls and a drier section, and a top felt passing thru said couch rolls and press rolls and then returning over said transfer rolls, of I second press rolls located between the first mentioned press rolls and said transfer rolls, said transfer rolls being locatedto arran the path of travel of said top felt above said second press rolls. 1

ea MAX OBERDORFER.

JOSEF E.'RYBERGL 

